People will take unknowns over the current status. The coal regions are still severely depressed. It likely doesn't matter to those people if $30B was spent if they didn't see an improvement in their own lives from it. Even if you get retrained, you have to leave the area to get a decent job about half of the time, which many don't want.

Sure, Trump's lie was better than Clinton's promise. Which explains why Trump won in 2016.

But it should have lost him the votes in 2024. "Fool me once, shame on you. Fool me twice, shame on me."

I think that depends on what Biden/Harris was promising them. If nothing really improved under Biden for them and Harris didn't have a good value proposition for them, then what was their alternative? Neither Trump nor Biden/Harris helped them, but one option is saying they will help them (or is more aligned with their values on non-economic topics).